Using properties file

Apache Log4j2 is the new version of the log4j and is used for printing logs when used in a Java program. In this tutorial we will setup a Maven project and use log4j2 to print logs from a simple Java class.

When asked for Group Id and Artifact Id , enter what you want, this will be used as name of the project and as package name for the Java project. To setup log4j2 for logging we will need log4j2 dependencies , which we will provide in our project's pom. Add the below code into your pom. We will create a Properties file to define the basic configurations for log4j like which appender to use Console appender, File appender etc and other setting like Pattern, log level etc.

Now we will create a Properties file with name log4j2. Now create a new file in this source folder with name log4j2. In the above Properties file we have specified a Console appender with basic information like name and a pattern to be used for printing log events. Also, we have specified the default root logger , log level for it and we have provided the reference of the Console appender to it. Once you are done with all this, right click on the main java class which is App.

You should get the following output in console:. App - This is a Debug Message! App - This is an Info Message!

App - And here comes the Error Message! RuntimeException: RunRunRun at com. To print logs in a file rather than printing on console, we will use File appender instead of Console appender in the Properties configuration file. Following is the Properties configuration to print logs in a file with name app. As you can see that we have provided the filename and a pattern just like the console appender example above. Run the Java class again to check of the log file is getting created.

You can even run the Java class multiple times and the logs will be appended in the same file. Using a File appender and storing logs in a file helps in storing the logs for later analysis. Recommended Articles. Article Contributed By :.

Easy Normal Medium Hard Expert. Writing code in comment? Please use ide. Load Comments. What's New. Most popular in Java. More related articles in Java. Properties configuration cannot handle some advanced features, such as custom error handlers, time-based rolling policies, nested appenders, and special types of appenders, such as async appenders. However, properties configuration is still being extensively used. In future posts, I will cover using other configuration options for Log4J 2.

This is to address logging configurations with more complex requirements. I have tried a lot but could not able to configure. Hi Ximanta, Im not used to configuring loggers.

However, i felt it was very convenient to enter the logger entry in a single line as done for log4j. Whereas, in log4j2 we have to specify a whole block of config. Ex:- In log4j we could x. I have tried but could not able to use them. Hi, I have a problem writing to the file. The file is created in the logs folder but nothing is written. That property just sets the filename for the appender to use.

Hi JT, Thanks for your answer. In fact I am getting the console logging, the file is created but the logs are not written in the file. I must be doing something wrong. In the example, the class is Log4J2PropertiesConf and the package is guru.

This line configures all loggers of the guru. I am facing the same issue. Were you able to figure what caused this? I am using log4j2. But, in our application, we might not configure all loggers individually. Such loggers will inherit the root logger properties including its level.

We specified the level as debug, as shown below. I am looking for system property input with default value setup for log path. For eg. Thanks so much for this concise explanation. This helped me tremendously.

I always find code examples to be the best way to learn these things. Can you configure async appenders this way? I also facing the same issue like file is creating but logs are not written in to the file as i am following same as above even not working. If want to print values for appender. Now, how to create multiple log files and persist logs into those log files. Hi, I have copied the code as mentioned above and changed the value for as below inlo4j2.

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What are Log4J 2 Configuration Files? I wanted to use properties file in my js file i don't know how to do that This is my js file code document. Improve this question. Gas Arundhati 99 Arundhati 99 19 4 4 bronze badges. The properties object contains key and value pair both as a string. It can be used to get property value based on the property key. The Properties class provides methods to get data from the properties file and store data into the properties file.

Moreover, it can be used to get the properties of a system. For eg db. So you need a hashmap that read a file.